Ammonia borane (AB) is a promising hydrogen storage material with up to 12 wt% obtainable from 100 to 150 C. Desorption temperatures can be lowered towards targets and kinetics improved by nanostructuring. We can synthesise nanostructured co-axial fibres of AB in a polymer sheath, using co-phase electrospinning techniques, and reduce the hydrogen desorption onset down to 85C. We find that the AB structure and desorption characteristics are dependent on the type of polymer used, which is a crucial finding for the purpose of controlling the desorption parameters. A high-resolution neutron diffraction study on co-axial PVDF/AB and PS/AB fibres, combined with INS, mass spectroscopy and isochoric analysis of the evolving chemicals through a phase transition temperature range, will enable an understanding of the reactions taking place and further optimisation of our synthesis process.